Tejbir Singh

Preparation of tablets rapidly disintegrating in saliva containing bitter taste-masked granules by compression method

The aim of this study was to prepare, using taste masked granules, rapidly disintegrating tablets of chlorpheniramine maleate, a bitter drug. The taste masked granules were prepared using aminoalkyl methacrylate copolymers (Eudragit E-100) by the extrusion method. In vitro release profile obtained at pH 6.8 indicate that perceivable amount of drug will not be released in saliva while high percent release (more than 80% in 30 min) would be obtained at acidic pH 1.2 of the stomach. These taste masked granules were directly compressed into tablets using sodium starch glycolate as a super-disintegrant. The prepared tablets containing the taste masked granules having sufficient strength of 3.5 kg/cm were evaluated for taste by both spectrophotometric method and through panel testing. Panel testing data collected from 20 healthy volunteers indicate successful formulation of oral fast disintegrating tablets which had good taste and disintegrated in the oral cavity within 30s.

Modeling the tool wear rate in powder mixed electro-discharge machining of titanium alloys using dimensional analysis of cryogenically treated electrodes and workpiece

Three grades of titanium alloy TITAN 15, TITAN 21, and TITAN 31 were machined using powder mixed electric discharge machining to study the effect of cryogenic treatment and its effect on tool wear rate (TWR). Thereafter, an attempt has been made to develop a mathematical model for predicting TWR using dimensional analysis using the outcome of the Taguchi model and thermo-physical properties of tool materials. The model shows the significant role of thermal conductivity on TWR in electric discharge machining of titanium alloys. The predicted values from the developed mathematical model were validated and were found to be in good agreement with the experimental results. Microscopic investigations on selected tool samples were performed using scanning electron microscope, energy-dispersive X-ray spectrometer, and X-ray diffraction. The results showed transfer of material on the tool surface from the workpiece, dielectric, and the powder.

Machining performance of cryogenically treated Ti–5Al–2.5Sn titanium alloy in electric discharge machining: A comparative study

In the present study, the effect of cryogenic treatment on the machining performance of Ti–5Al–2.5Sn alpha titanium alloy was investigated during electric discharge machining. Untreated, shallow cryogenically treated (−110u2009℃), and deep cryogenically treated (−184u2009℃) titanium alloys were machined by varying current and pulse-on-time. The machining performance was measured in terms of higher material removal rate and microhardness and low tool wear rate and surface roughness. The results showed a significant improvement in the machining performance with deep cryogenically treated alloy when compared with shallow and untreated alloy. Current and pulse-on-time also affected the machinability of titanium alloy. Higher material removal rate and microhardness were observed when titanium alloy was machined at high current and pulse-on-time. During machining, carbon was deposited on the machined surface due to the breakdown of hydrocarbon dielectric at high temperature thereby, affecting its properties.

Study the Surface Characteristics of Cryogenically Treated Tool-Electrodes in Powder Mixed Electric Discharge Machining Process

The present experimental study has been focused to evaluate surface characteristics of cryogenically-treated (shallow/deep) tool-electrodes using powder mixed electric discharge machining. Due to the continuously growing demand of complex and precise parts, tool-electrodes have its own importance, because quality of the machined parts depends upon the surface quality of electrode. On the analogy, eighteen experiments were performed based on L18 orthogonal array of Taguchi’s methodology, which consist eight input parameters. Analysis of variance (ANOVA) was employed to designate the level of significance of input parameters. Electrode material has maximum influence followed by the current and pulse on-time on electrode finish. The combination of optimum factor’s level of identified parameters was determined using Taguchi’s technique for single response. Confirmation experiments were conducted using suggested optimal parameters with its respective level to minimize the tool-electrode surface roughness. Surface characteristics of tool-electrodes were analyzed using Scanning Electron Microscope (SEM) and Energy Dispersive Spectrograph (EDS) followed by X-ray diffraction (XRD) on selected samples. The results exposed that significant material transfer from workpiece and powder mixed dielectric fluid in compound form on the tool surface.